We use "bring on" because it's the correct phrasal verb in this context (meaning "to cause").
We use the bare infinitive because that's what we use after "All it/he/she/etc does is..."
I don't like John. All he does is complain.
I don't eat apples. All they do is give me stomach ache.
There is a man on that street corner and all he does is sing "Jingle Bells".
School's boring. We're there for 7 hours and all we do is listen to teachers talk.
Student or Learner